This invention relates to a fiber feeding arrangement for open-end friction spinning. Preferred embodiments usable with the invention have at least one friction roller forming a yarn-forming zone and a feeding and opening device that contains an opening roller arranged in an opening roller housing. A fiber-feeding duct starts at the opening roller and extends to the at least one friction roller to a mouth disposed opposite the yarn-forming zone.
In the case of an arrangement of this type disclosed in German Unexamined Published Application (DE-OS) No. 3,300,637 the fiber feeding duct is formed in two parts. The first part of the fiber feeding duct is a component of an opening roller housing. The second part of the fiber feeding duct is a component of a covering that can be moved away for exposing the friction rollers and the wedge-shaped gap formed by them. By means of this type of construction good accessibility to the yarn-forming zone is possible for servicing, however, in this arrangement a parting line in the fiber feeding duct has to be accepted. It has been determined that such a parting line may impair the spinning results. Presumably, the reason for such impairment relates to the parting line influencing the air flows that significantly determine the friction effect and flow to the yarn-forming zone.
In the case of the diagrammatically represented arrangement for open-end friction spinning disclosed in German Published Unexamined Application (DE-OS) No. 2,714,089, it is also shown to develop a fiber feeding duct in one piece with an opening roller housing. It is not shown in this document how the area of the friction rollers and of the yarn-forming zone can be exposed for servicing.
An arrangement in also disclosed European Unexamined Published Application (EP-OS) No. 52,412 with a fiber feeding duct arranged stationarily at a machine part. For the exposing of the yarn-forming zone, one of the two friction rollers that forms a wedge-shaped gap as the yarn-forming zone is arranged pivotably.
This invention is based on the objective of providing an arrangement of the initially mentioned type wherein, on the one hand, a parting line in the fiber feeding duct is avoided, while, on the other hand, the at least one friction roller and the yarn-forming zone can be readily exposed for servicing.
The objective is achieved according to the invention by providing that the fiber feeding duct is a one-piece component that is mounted at the opening roller housing which, by means of a holding device, is held in a stationary position, the holding device containing a securing device permitting a quick removal of the opening roller housing.
By means of this arrangement, any parting line in the area of the fiber feeding duct is avoided, while, nevertheless, the at least one friction roller and the yarn-forming zone, can be exposed in a simple way by the removal of the opening roller housing together with the fiber feeding duct.
In order to provide a simple and secure holding means for the opening roller housing, it is provided according to a further development of preferred embodiments of the invention that the opening roller housing is fitted with a guide means onto a shank that extends substantially perpendicularly to the yarn-forming zone and is stationarily mounted at the machine frame, and is held by a securing means aligned in circumferential direction to the shank. In the case of this embodiment, the opening roller housing can be removed in a simple way and installed by the pulling-off and refitting the same onto the shank. In a further development, it is provided that in the operating position, the opening roller housing is held with a stop face at an axial stop of the shank. Thus the position of the opening roller, and especially also the position of the fiber feeding duct, with respect to the yarn-forming zone is determined precisely. In an advantageous further development of such embodiments, it is provided that in the operating position, the opening roller housing is pressed against the stop of the shank with an elastic element that is mounted at a covering that can be moved away from the opening of the arrangement. In this way, a quick closure is provided that does not require any separate actuating because the covering already largely takes over the function of the quick secure closure.
In a further development of preferred embodiments of the invention, it is provided that the fiber feeding duct is fitted into a recess of the opening roller housing, a support being provided that defines the fitted-in position. As a result, it is possible to arrange the fiber feeding duct detachably in the opening roller housing so that it can be exchanged and replaced when required. In certain circumstances, it is also contemplated in this case to exchange the fiber duct for the adaptation to special spinning conditions, with one that has a more suitable shape for these spinning conditions.
In a further development of a preferred embodiments of the invention, it is provided that the fiber feeding duct is formed from a flat piece of pipe that has an essentially oval cross-section that tapers away from the opening roller, the piece of pipe being arranged tangentially to the circumference of the opening roller, its larger cross-sectional length corresponding at least to the width of a set of opening roller means. The duct is equipped with a mouth extending in a slot-shaped manner in the direction of the yarn-forming zone and diagonally to the longitudinal axis of the piece of pipe. Such a fiber feeding duct may be formed to be very flat so that it can be moved very closely to the yarn-forming zone, even though this zone is formed by a wedge-shaped gap between two friction rollers.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawings which show, for purposes of illustration only, an embodiment in accordance with the present invention.